This invention relates generally to copying machines and particularly to apparatus for stacking large copy sheets discharged from a whiteprint, blueprint or similar copying machine.
It is widely known to provide stacking devices or trays at the exit ends of copying machines for collecting copy sheets and neatly stacking the sheets for removal from the machine. Most such stacking devices normally have been designed for relatively small copy sheets and often rely upon the inherent stiffness of the sheets to facilitate the positioning and stacking of the sheets. For instance, the inherent stiffness of relatively small copy sheets often is utilized to advantage in transporting the sheets and deflecting the sheets into stacking position.
Devices of the character described above are not applicable for use with whiteprint, blueprint or similar copying machines which handle relatively large copy sheets. One such machine uses the diazo process where a translucent original is placed upon a relatively large sheet of sensitized diazo coated paper and the two sheets are fed together through the machine. The sheets are carried around a transparent cylinder which contains an ultraviolet lamp. Wherever the light passes through the original to the copy the sensitized coating on the copy is decomposed leaving the copy paper white. Wherever the image on the original shields the copy paper from the light, the sensistized coating will remain as a latent image. After being separated from the original, the exposed copy paper passes into a developer section where a thin film of activator is applied. The activator combines with the coating in the latent image area and forms a visible image on the copy material. The copy then emerges from the machine as a flat, dry print ready for immediate use. This is but one type of copying machine to which the present invention is applicable, in that the size of the copy sheets may be as large as 24.times.36 inches.
It is readily apparent that because of the large size sheets used in whiteprint and blueprint copying machines, most known stacking devices cannot be employed because of the lack of inherent stiffness in the large size copy sheets. In essence, the large sheets are somewhat "limp" as they emerge from the copying machine.
Machines of the character described also are manufactured in relatively large "console" as well as smaller "tabletop" models. In the console models, the sheets normally are fed into the front of the machine and are discharged from the rear of the machine. In tabletop models, the sheets are fed into the front of the machine and also are discharged from the front of the machine. Copending patent application Ser. No. 602,778, filed Apr. 23, 1984, and assigned to the assignee of the instant application, discloses an apparatus for a console-type machine which not only stacks the large copy sheets but inverts the orientation of the sheets discharged from the rear of the machine.
As with the need satisfied by the apparatus of that application, there is a definite need for a simple apparatus for stacking large copy sheets discharged from the front of a smaller tabletop machine. Heretofore, an operator loaded the machine with individual sets of sheets, i.e. the original and the coated copy paper, and manually removed the sheets as they were discharged from the machine. The present invention is directed to eliminating this burdensome manual unloading of such whiteprint, blueprint or similar machines.